Fire pump control systems are commonly used in large buildings to control the flow of water to sprinkler heads as part of a fire suppression system. A fire pump control system operates a pump system for directing high pressure water to the sprinkler heads.
The pump control system is connected to various fire detectors and sensors and activates a pump in the event of a fire to supply the water to the desired location. The control system typically controls the water pressure, flow rate, starting of the pump and the stopping of the pump.
In a building or location where the electrical power supply is limited or unreliable, a gasoline or diesel powered generator can be used to provide electrical power to operate the water pump. Diesel engines used in fire suppression systems are required to be operated periodically and typically once a week to ensure proper operation. The testing operation requires that various measurements be made and recorded to establish compliance with the appropriate codes and regulations that govern fire suppression systems, for example, water pressure level, flow rate, fuel level and operating time and frequency. These operating functions and recorded measurements are stored and analyzed by a suitable microprocessor so that selected information can be recovered by the operator.
Some fire suppression systems that include an internal combustion engine to provide electrical power to the pump mechanism are able to operate on electrical power supplied through standard utility power lines. A number of these fire suppression systems are able to operate alternatively with electrical power supplied through the utility lines, or electrical power supplied by a generator operated by the internal combustion engine. Current regulations require that the control system for operating the pump, valves, and the like, be separate from the switching mechanism that switches between a primary power source such as an AC power source provided via utility lines and the back-up generator. The control system and transfer switch are assembled in separate housings or cabinets. These devices typically require large amounts of floor space which increases the difficulty of constructing and assembling such systems and decreases efficient use of limited pump room or utility room floor space.
The electric motors that operate the pumps are generally large and powerful and require large amounts of electrical power. In particular, these large electrical motors require large amounts of electrical power to start the motors which can cause sudden increases and decreases in the water pressure within the water pipes of the system. These sudden changes in water pressure, and particularly a sudden increase in water pressure, can cause damage to the valves, pumps, pressure regulators and other equipment.
To overcome the problem associated with sudden water pressure changes, systems have been developed to control the voltage supplied to the electric motors that operate the pumps. Reducing the starting voltage can be attained by the design of the motor. The reduced voltage enables the motor to start at slower speeds to reduce the surging and sudden increase in water pressure. As the voltage increases, the motor speed increases to attain the desired water pressure. The controlled starting of the electric motors is commonly referred to as soft start. Examples of soft start motors are disclosed in U.S. Pat. No. 5,221,189 to Henningsen, U.S. Pat. No. 3,859,565 to Henningsen and U.S. Pat. No. 4,611,290 to Henningsen, which are hereby incorporated herein by reference.
As stated above, some existing fire pump control devices are used in conjunction with a transfer switch assembly to ensure electrical power is continuously supplied to the pump control system, even during an outage of the primary power source. The transfer switches of these prior devices are provided in a separate enclosure according to current regulations and are connected to the pump control system by a suitable electrical connection. These prior devices, with their separate transfer switching enclosures, are mounted side-by-side, and thus, require a significant amount of floor space. For example, U.S. Pat. No. 5,221,189 discloses a fire pump controller having separate cabinets for the starting components and the main fire pump control.
Various fire pump control systems have been developed to supply water under pressure to a fire suppression system. Examples of such systems are disclosed in U.S. Pat. No. 3,974,879 and U.S. Pat. No. 3,544,235 which are hereby incorporated by reference in their entirety. These devices have been generally effective for their intended purpose but have not overcome all of the limitations and deficiencies of the prior systems. Accordingly, there is a continuing need in the industry for an improved fire pump control system.